The bone marrow
cells came from patients’ own blood and were injected into their
ailing hearts. The cells fueled new cell growth, which
strengthened the heart’s pumping capacity.

“These results
demonstrate for the first time that transplantation of a
person’s own stem cells through direct intracoronary injection
increased cardiac function, blood flow and metabolism in the
damaged zone,” said senior author Bodo E. Strauer, M.D.,
professor of medicine at Heinrich Heine University in
Düsseldorf, Germany.

“If a
prospective, randomized, multicenter study confirms these
encouraging results, a new therapy for heart attacks could be in
reach,” he said.

When a person
suffers a heart attack, the heart can develop left ventricular
remodeling, a process by which heart muscle cells stretch in
response to damage. Over time, the stretched muscle weakens and
can lead to heart failure.

In March 2001, in
a first-of-its-kind procedure, Strauer and his colleagues
treated an acute heart attack patient with stem cells harvested
from his own bone marrow. The cells were implanted into the
damaged muscle, using a catheter threaded into a heart artery.

Three months
later, the patient had less heart muscle damage and an increased
ejection fraction, a measure of the heart’s pumping ability.

The study
reported today is a follow-up to that small trial.

The German team
enrolled 40 heart attack patients who had been treated with
balloon angioplasty and also had a mesh tube called a stent
placed into the vessel to help prop it open.

Twenty patients
agreed to accept the stem cells; 20 others who declined the
experimental procedure comprised the control group.

All patients had
angiography and a similar imaging examination called left
ventriculography to assess their heart’s geometry. These exams
were given before enrollment and three months later.

Four to eight
days after the patients’ heart attacks, doctors obtained bone
marrow cells from members of the treatment group. Stem cells
were isolated from the marrow, cultured overnight, and
transplanted the following day.

A catheter was
pushed into the blocked heart artery that caused the heart
attack and balloon angioplasty was performed for two to four
minutes. Small amounts (3 - 4 mL) of a solution containing the
stem cells were infused into the damaged heart tissue at the
re-opened site four or five times.

After three
months, the stem cell patients’ average area of damage decreased
from 33 percent of the left ventricle’s circumference to 14
percent.

The contraction
speed of the heart went from 1.5 centimeters per second (cm/s)
in the treated group to 3.3 cm/s. The fraction of blood ejected
by the heart rose from 55 percent to 65 percent.

Ten patients had
a test that measures the average glucose uptake, which indicates
the metabolism rate of cells. Their glucose uptake increased
from 47 percent to 58 percent. The amount of blood perfusing
the damaged area rose from 49 percent to 58 percent.

The team said
these improvements indicate that the transplanted stem cells are
associated with new heart muscle and new blood vessels.

Several research
teams have investigated the use of stem cells harvested from
bone marrow to reverse the muscle damage caused by a heart
attack. Stem cells are immature cells that still can transform,
or differentiate, into different types of cells, such as heart
muscle and blood vessels.